mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
628 lines
15 KiB
C
628 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
|
|
* RTAS calls are available
|
|
*/
|
|
|
|
/*
|
|
* RTAS watchdog driver
|
|
*
|
|
* (C) Copyright IBM Corp. 2005
|
|
* device driver to exploit watchdog RTAS functions
|
|
*
|
|
* Authors : Utz Bacher <utz.bacher@de.ibm.com>
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/module.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/types.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <asm/rtas.h>
|
|
|
|
#define WDRTAS_MAGIC_CHAR 42
|
|
#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
|
|
WDIOF_MAGICCLOSE)
|
|
|
|
MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
|
|
MODULE_DESCRIPTION("RTAS watchdog driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT;
|
|
static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
|
|
static char wdrtas_expect_close;
|
|
|
|
static int wdrtas_interval;
|
|
|
|
#define WDRTAS_THERMAL_SENSOR 3
|
|
static int wdrtas_token_get_sensor_state;
|
|
#define WDRTAS_SURVEILLANCE_IND 9000
|
|
static int wdrtas_token_set_indicator;
|
|
#define WDRTAS_SP_SPI 28
|
|
static int wdrtas_token_get_sp;
|
|
static int wdrtas_token_event_scan;
|
|
|
|
#define WDRTAS_DEFAULT_INTERVAL 300
|
|
|
|
#define WDRTAS_LOGBUFFER_LEN 128
|
|
static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
|
|
|
|
|
|
/*** watchdog access functions */
|
|
|
|
/**
|
|
* wdrtas_set_interval - sets the watchdog interval
|
|
* @interval: new interval
|
|
*
|
|
* returns 0 on success, <0 on failures
|
|
*
|
|
* wdrtas_set_interval sets the watchdog keepalive interval by calling the
|
|
* RTAS function set-indicator (surveillance). The unit of interval is
|
|
* seconds.
|
|
*/
|
|
|
|
static int wdrtas_set_interval(int interval)
|
|
{
|
|
long result;
|
|
static int print_msg = 10;
|
|
|
|
/* rtas uses minutes */
|
|
interval = (interval + 59) / 60;
|
|
|
|
result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
|
|
WDRTAS_SURVEILLANCE_IND, 0, interval);
|
|
if (result < 0 && print_msg) {
|
|
pr_err("setting the watchdog to %i timeout failed: %li\n",
|
|
interval, result);
|
|
print_msg--;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
#define WDRTAS_SP_SPI_LEN 4
|
|
|
|
/**
|
|
* wdrtas_get_interval - returns the current watchdog interval
|
|
* @fallback_value: value (in seconds) to use, if the RTAS call fails
|
|
*
|
|
* returns the interval
|
|
*
|
|
* wdrtas_get_interval returns the current watchdog keepalive interval
|
|
* as reported by the RTAS function ibm,get-system-parameter. The unit
|
|
* of the return value is seconds.
|
|
*/
|
|
static int wdrtas_get_interval(int fallback_value)
|
|
{
|
|
long result;
|
|
char value[WDRTAS_SP_SPI_LEN];
|
|
|
|
spin_lock(&rtas_data_buf_lock);
|
|
memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
|
|
result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
|
|
WDRTAS_SP_SPI, __pa(rtas_data_buf),
|
|
WDRTAS_SP_SPI_LEN);
|
|
|
|
memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
|
|
spin_unlock(&rtas_data_buf_lock);
|
|
|
|
if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
|
|
pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n",
|
|
result);
|
|
return fallback_value;
|
|
}
|
|
|
|
/* rtas uses minutes */
|
|
return ((int)value[2]) * 60;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_timer_start - starts watchdog
|
|
*
|
|
* wdrtas_timer_start starts the watchdog by calling the RTAS function
|
|
* set-interval (surveillance)
|
|
*/
|
|
static void wdrtas_timer_start(void)
|
|
{
|
|
wdrtas_set_interval(wdrtas_interval);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_timer_stop - stops watchdog
|
|
*
|
|
* wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
|
|
* set-interval (surveillance)
|
|
*/
|
|
static void wdrtas_timer_stop(void)
|
|
{
|
|
wdrtas_set_interval(0);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_timer_keepalive - resets watchdog timer to keep system alive
|
|
*
|
|
* wdrtas_timer_keepalive restarts the watchdog timer by calling the
|
|
* RTAS function event-scan and repeats these calls as long as there are
|
|
* events available. All events will be dumped.
|
|
*/
|
|
static void wdrtas_timer_keepalive(void)
|
|
{
|
|
long result;
|
|
|
|
do {
|
|
result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
|
|
RTAS_EVENT_SCAN_ALL_EVENTS, 0,
|
|
(void *)__pa(wdrtas_logbuffer),
|
|
WDRTAS_LOGBUFFER_LEN);
|
|
if (result < 0)
|
|
pr_err("event-scan failed: %li\n", result);
|
|
if (result == 0)
|
|
print_hex_dump(KERN_INFO, "dumping event, data: ",
|
|
DUMP_PREFIX_OFFSET, 16, 1,
|
|
wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false);
|
|
} while (result == 0);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_get_temperature - returns current temperature
|
|
*
|
|
* returns temperature or <0 on failures
|
|
*
|
|
* wdrtas_get_temperature returns the current temperature in Fahrenheit. It
|
|
* uses the RTAS call get-sensor-state, token 3 to do so
|
|
*/
|
|
static int wdrtas_get_temperature(void)
|
|
{
|
|
int result;
|
|
int temperature = 0;
|
|
|
|
result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
|
|
|
|
if (result < 0)
|
|
pr_warn("reading the thermal sensor failed: %i\n", result);
|
|
else
|
|
temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
|
|
|
|
return temperature;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_get_status - returns the status of the watchdog
|
|
*
|
|
* returns a bitmask of defines WDIOF_... as defined in
|
|
* include/linux/watchdog.h
|
|
*/
|
|
static int wdrtas_get_status(void)
|
|
{
|
|
return 0; /* TODO */
|
|
}
|
|
|
|
/**
|
|
* wdrtas_get_boot_status - returns the reason for the last boot
|
|
*
|
|
* returns a bitmask of defines WDIOF_... as defined in
|
|
* include/linux/watchdog.h, indicating why the watchdog rebooted the system
|
|
*/
|
|
static int wdrtas_get_boot_status(void)
|
|
{
|
|
return 0; /* TODO */
|
|
}
|
|
|
|
/*** watchdog API and operations stuff */
|
|
|
|
/* wdrtas_write - called when watchdog device is written to
|
|
* @file: file structure
|
|
* @buf: user buffer with data
|
|
* @len: amount to data written
|
|
* @ppos: position in file
|
|
*
|
|
* returns the number of successfully processed characters, which is always
|
|
* the number of bytes passed to this function
|
|
*
|
|
* wdrtas_write processes all the data given to it and looks for the magic
|
|
* character 'V'. This character allows the watchdog device to be closed
|
|
* properly.
|
|
*/
|
|
static ssize_t wdrtas_write(struct file *file, const char __user *buf,
|
|
size_t len, loff_t *ppos)
|
|
{
|
|
int i;
|
|
char c;
|
|
|
|
if (!len)
|
|
goto out;
|
|
|
|
if (!wdrtas_nowayout) {
|
|
wdrtas_expect_close = 0;
|
|
/* look for 'V' */
|
|
for (i = 0; i < len; i++) {
|
|
if (get_user(c, buf + i))
|
|
return -EFAULT;
|
|
/* allow to close device */
|
|
if (c == 'V')
|
|
wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
|
|
}
|
|
}
|
|
|
|
wdrtas_timer_keepalive();
|
|
|
|
out:
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_ioctl - ioctl function for the watchdog device
|
|
* @file: file structure
|
|
* @cmd: command for ioctl
|
|
* @arg: argument pointer
|
|
*
|
|
* returns 0 on success, <0 on failure
|
|
*
|
|
* wdrtas_ioctl implements the watchdog API ioctls
|
|
*/
|
|
|
|
static long wdrtas_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
int __user *argp = (void __user *)arg;
|
|
int i;
|
|
static const struct watchdog_info wdinfo = {
|
|
.options = WDRTAS_SUPPORTED_MASK,
|
|
.firmware_version = 0,
|
|
.identity = "wdrtas",
|
|
};
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
|
|
return -EFAULT;
|
|
return 0;
|
|
|
|
case WDIOC_GETSTATUS:
|
|
i = wdrtas_get_status();
|
|
return put_user(i, argp);
|
|
|
|
case WDIOC_GETBOOTSTATUS:
|
|
i = wdrtas_get_boot_status();
|
|
return put_user(i, argp);
|
|
|
|
case WDIOC_GETTEMP:
|
|
if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
|
|
return -EOPNOTSUPP;
|
|
|
|
i = wdrtas_get_temperature();
|
|
return put_user(i, argp);
|
|
|
|
case WDIOC_SETOPTIONS:
|
|
if (get_user(i, argp))
|
|
return -EFAULT;
|
|
if (i & WDIOS_DISABLECARD)
|
|
wdrtas_timer_stop();
|
|
if (i & WDIOS_ENABLECARD) {
|
|
wdrtas_timer_keepalive();
|
|
wdrtas_timer_start();
|
|
}
|
|
/* not implemented. Done by H8
|
|
if (i & WDIOS_TEMPPANIC) {
|
|
} */
|
|
return 0;
|
|
|
|
case WDIOC_KEEPALIVE:
|
|
wdrtas_timer_keepalive();
|
|
return 0;
|
|
|
|
case WDIOC_SETTIMEOUT:
|
|
if (get_user(i, argp))
|
|
return -EFAULT;
|
|
|
|
if (wdrtas_set_interval(i))
|
|
return -EINVAL;
|
|
|
|
wdrtas_timer_keepalive();
|
|
|
|
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
|
|
wdrtas_interval = i;
|
|
else
|
|
wdrtas_interval = wdrtas_get_interval(i);
|
|
fallthrough;
|
|
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(wdrtas_interval, argp);
|
|
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* wdrtas_open - open function of watchdog device
|
|
* @inode: inode structure
|
|
* @file: file structure
|
|
*
|
|
* returns 0 on success, -EBUSY if the file has been opened already, <0 on
|
|
* other failures
|
|
*
|
|
* function called when watchdog device is opened
|
|
*/
|
|
static int wdrtas_open(struct inode *inode, struct file *file)
|
|
{
|
|
/* only open once */
|
|
if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
|
|
atomic_dec(&wdrtas_miscdev_open);
|
|
return -EBUSY;
|
|
}
|
|
|
|
wdrtas_timer_start();
|
|
wdrtas_timer_keepalive();
|
|
|
|
return stream_open(inode, file);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_close - close function of watchdog device
|
|
* @inode: inode structure
|
|
* @file: file structure
|
|
*
|
|
* returns 0 on success
|
|
*
|
|
* close function. Always succeeds
|
|
*/
|
|
static int wdrtas_close(struct inode *inode, struct file *file)
|
|
{
|
|
/* only stop watchdog, if this was announced using 'V' before */
|
|
if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
|
|
wdrtas_timer_stop();
|
|
else {
|
|
pr_warn("got unexpected close. Watchdog not stopped.\n");
|
|
wdrtas_timer_keepalive();
|
|
}
|
|
|
|
wdrtas_expect_close = 0;
|
|
atomic_dec(&wdrtas_miscdev_open);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_temp_read - gives back the temperature in fahrenheit
|
|
* @file: file structure
|
|
* @buf: user buffer
|
|
* @count: number of bytes to be read
|
|
* @ppos: position in file
|
|
*
|
|
* returns always 1 or -EFAULT in case of user space copy failures, <0 on
|
|
* other failures
|
|
*
|
|
* wdrtas_temp_read gives the temperature to the users by copying this
|
|
* value as one byte into the user space buffer. The unit is Fahrenheit...
|
|
*/
|
|
static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
int temperature = 0;
|
|
|
|
temperature = wdrtas_get_temperature();
|
|
if (temperature < 0)
|
|
return temperature;
|
|
|
|
if (copy_to_user(buf, &temperature, 1))
|
|
return -EFAULT;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_temp_open - open function of temperature device
|
|
* @inode: inode structure
|
|
* @file: file structure
|
|
*
|
|
* returns 0 on success, <0 on failure
|
|
*
|
|
* function called when temperature device is opened
|
|
*/
|
|
static int wdrtas_temp_open(struct inode *inode, struct file *file)
|
|
{
|
|
return stream_open(inode, file);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_temp_close - close function of temperature device
|
|
* @inode: inode structure
|
|
* @file: file structure
|
|
*
|
|
* returns 0 on success
|
|
*
|
|
* close function. Always succeeds
|
|
*/
|
|
static int wdrtas_temp_close(struct inode *inode, struct file *file)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_reboot - reboot notifier function
|
|
* @nb: notifier block structure
|
|
* @code: reboot code
|
|
* @ptr: unused
|
|
*
|
|
* returns NOTIFY_DONE
|
|
*
|
|
* wdrtas_reboot stops the watchdog in case of a reboot
|
|
*/
|
|
static int wdrtas_reboot(struct notifier_block *this,
|
|
unsigned long code, void *ptr)
|
|
{
|
|
if (code == SYS_DOWN || code == SYS_HALT)
|
|
wdrtas_timer_stop();
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
/*** initialization stuff */
|
|
|
|
static const struct file_operations wdrtas_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = wdrtas_write,
|
|
.unlocked_ioctl = wdrtas_ioctl,
|
|
.compat_ioctl = compat_ptr_ioctl,
|
|
.open = wdrtas_open,
|
|
.release = wdrtas_close,
|
|
};
|
|
|
|
static struct miscdevice wdrtas_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &wdrtas_fops,
|
|
};
|
|
|
|
static const struct file_operations wdrtas_temp_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.read = wdrtas_temp_read,
|
|
.open = wdrtas_temp_open,
|
|
.release = wdrtas_temp_close,
|
|
};
|
|
|
|
static struct miscdevice wdrtas_tempdev = {
|
|
.minor = TEMP_MINOR,
|
|
.name = "temperature",
|
|
.fops = &wdrtas_temp_fops,
|
|
};
|
|
|
|
static struct notifier_block wdrtas_notifier = {
|
|
.notifier_call = wdrtas_reboot,
|
|
};
|
|
|
|
/**
|
|
* wdrtas_get_tokens - reads in RTAS tokens
|
|
*
|
|
* returns 0 on success, <0 on failure
|
|
*
|
|
* wdrtas_get_tokens reads in the tokens for the RTAS calls used in
|
|
* this watchdog driver. It tolerates, if "get-sensor-state" and
|
|
* "ibm,get-system-parameter" are not available.
|
|
*/
|
|
static int wdrtas_get_tokens(void)
|
|
{
|
|
wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
|
|
if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
|
|
pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n");
|
|
}
|
|
|
|
wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
|
|
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
|
|
pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n",
|
|
WDRTAS_DEFAULT_INTERVAL);
|
|
}
|
|
|
|
wdrtas_token_set_indicator = rtas_token("set-indicator");
|
|
if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
|
|
pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n");
|
|
return -EIO;
|
|
}
|
|
|
|
wdrtas_token_event_scan = rtas_token("event-scan");
|
|
if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
|
|
pr_err("couldn't get token for event-scan. Terminating watchdog code.\n");
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_unregister_devs - unregisters the misc dev handlers
|
|
*
|
|
* wdrtas_register_devs unregisters the watchdog and temperature watchdog
|
|
* misc devs
|
|
*/
|
|
static void wdrtas_unregister_devs(void)
|
|
{
|
|
misc_deregister(&wdrtas_miscdev);
|
|
if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
|
|
misc_deregister(&wdrtas_tempdev);
|
|
}
|
|
|
|
/**
|
|
* wdrtas_register_devs - registers the misc dev handlers
|
|
*
|
|
* returns 0 on success, <0 on failure
|
|
*
|
|
* wdrtas_register_devs registers the watchdog and temperature watchdog
|
|
* misc devs
|
|
*/
|
|
static int wdrtas_register_devs(void)
|
|
{
|
|
int result;
|
|
|
|
result = misc_register(&wdrtas_miscdev);
|
|
if (result) {
|
|
pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n");
|
|
return result;
|
|
}
|
|
|
|
if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
|
|
result = misc_register(&wdrtas_tempdev);
|
|
if (result) {
|
|
pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n");
|
|
wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_init - init function of the watchdog driver
|
|
*
|
|
* returns 0 on success, <0 on failure
|
|
*
|
|
* registers the file handlers and the reboot notifier
|
|
*/
|
|
static int __init wdrtas_init(void)
|
|
{
|
|
if (wdrtas_get_tokens())
|
|
return -ENODEV;
|
|
|
|
if (wdrtas_register_devs())
|
|
return -ENODEV;
|
|
|
|
if (register_reboot_notifier(&wdrtas_notifier)) {
|
|
pr_err("could not register reboot notifier. Terminating watchdog code.\n");
|
|
wdrtas_unregister_devs();
|
|
return -ENODEV;
|
|
}
|
|
|
|
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
|
|
wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
|
|
else
|
|
wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wdrtas_exit - exit function of the watchdog driver
|
|
*
|
|
* unregisters the file handlers and the reboot notifier
|
|
*/
|
|
static void __exit wdrtas_exit(void)
|
|
{
|
|
if (!wdrtas_nowayout)
|
|
wdrtas_timer_stop();
|
|
|
|
wdrtas_unregister_devs();
|
|
|
|
unregister_reboot_notifier(&wdrtas_notifier);
|
|
}
|
|
|
|
module_init(wdrtas_init);
|
|
module_exit(wdrtas_exit);
|